液相各检测器介绍

1、LIQUID CLIQUID CHROMOMATOOGRAPHY D DETECCTOORSAnalalyt tes s that that elutlute from a colum from a column need to b to be det tectcted to toObtaObtain a chromato a chromatogramram. D Det tector ctor is a crs a crit tical compocal component tOf aOf any LC s LC syststem m. Th he follow following t ty

2、p pes of s of det tectors arctors are us used:11. . U UV-v vis siblble det tectorctor22. . Fluorluorescscenc ce det tectorctor33. . El lectrctrical cocal conductuctiv vit ty det tectorctor44. . Refractfractiv ve index det tectorctor5. Mass spMass spectral ctral det tectorctorU UV-VI ISI IBLLE D DETE

3、CCTOORSSININGLLE WAVELLENNGTH D DETECCTOORSingl le wav wavel length th det tectors coctors cons sist of thst of the follow followingCompoComponentsts:11. . A low pr low pressurssure m mercurrcury discharscharge lamp that lamp that em mits lts lighthtI In th the U UV a and v vis siblble r regio ons s

4、.22. A focus focusing quartuartz l lens s.33. A cut cut-off foff filtlter (broar (broad ba band or ba or band-pass) that allowspass) that allowsSp pec cif fic wavc wavel length rath ranges to bs to be tra transmsmitttted to th to the Samplample.44. Ref fer renc ce a and sampl sample c cells of small

5、 volumlls of small volume (m (microlcrolit tersrs) ).5. Photomulthotomultiplplier r or photo cor photo cells to molls to monitor thtor the Absorptbsorptio on of l of lightht.66. Absorbabsorbanc ce is calculats calculated from from Beer rs laws law: LoLog I IT/I IOO = l c l c = AVARI IABLLE WAVELLENN

6、GTH D DETECCTOORVARI IABLLE WAVELLENNGTH D DETECCTOOR (CON(CONTD)D)Varariablable wav wavel length th det tector coctor cons sists of thsts of the follow following compo componentsts:11. . A deututer rium aum and or tu or tungststen lamp to cov lamp to cover thr the uv uv aandVis siblble sp spectral

7、ractral ranges s.22. Coll Collimatmating m mirrors that focus thrrors that focus the sourc source b beam oam on to toA diffractffractio on gratrating. Th he diffractffractio on gratrating r resolvsolves spolpolychromatchromatic bc beam am into to its compots component wavt wavel lengthsths.Th he sp

8、spectral rctral resolutsolutio on is a fus a functctio on of th of the numbumber ofr ofLLines s in th the gratrating. Th his arras arrangem ment allows a spt allows a spec cif fic cWavavel length to bth to be chos chosen for for det tectcting th the a analalyt tes s.33. A small volum small volume c

9、cell ll into whto which thch the elutluting mob mobil le phas phaseIs fIs fed.44. A l lens s in th the fro front at and bac back of th of the c cell to focus thll to focus the giv venWavavel length lth light ht into thto the sampl sample a and th the tra transmsmitttted l lighthtI Into thto the phot

10、omult photomultiplplier r.FLUOLUORESCCENCNCE D DETECCTOORFLUOLUORESCCENCNCE D DETECCTOORA fluor fluorescscenc ce det tector has thctor has the follow following compo componentsts:11. . A pol polychromatchromatic lc light sourcht source such as as a such as as a xeno on lamp lamp.22. Th his ls light

11、ht is focuss focused o onto a to a diffractffractio on gratrating wh whichchAllows thllows the exc citattatio on wav wavel length to bth to be chos chosen.33. Th he chos chosen wav wavel length lth light ht is passs passed throu through thh the Samplample a and r ref fer renc ce c cellslls.44. Th he

12、 l light ht em mitttted from th from the sampl sample c cell ll is colls collectcted at at 90o o to th to the inc cident lt lightht.5. Th his s is s inc cident ot on a s a secocond gratrating b beforfore b being s sent tTo tho the photomult photomultiplplier r for for det tectctio on.66. Th he exit

13、t gratrating enablables s det tectctio on at a chos at a chosen em missssio onWavavel lengthth.77. Fluorluorescscenc ce is s inh her rentltly mor more s sens sit tiv ve tha than Absorptbsorptio on a and has a lar has a larger lr liner r dynamamic rac range.ELLECCTRICICAL CONDUCL CONDUCTI IVI ITY D D

14、ETECCTOOREl lectrctrical cocal conductuctiv vit ty det tector ctor is uss used in io on ChromatoChromatographraphy. It m It measurasures ths the r res sistastanc ce a and h henc ceththe co conductuctiv vit ty of th of the solut solutio on from wh from which a sch a signal al is sGeneratrated for for

15、 det tectctio on.ELLECCTRICICAL CONDUCL CONDUCTI IVI ITY D DETECCTOORCoConductauctanc ce of a of a giv ven solut solutio on is C as C and is s giv ven b by C C = 1 1/R = a a/l lWh her re R = r res sistastanc ce in ohms ohms = sp spec cif fic coc conductauctanc ce a a = cross cross-s sectctio onal ar

16、al area of tha of the el lectroctrode l l = distastanc ce b betwtween th the el lectroctrodes sEqu uivalvalent cot conductauctanc ce is s def fined as as = 1 1000 /c cWh her re c c is ths the co conc centrattratio on of th of the el lectrolctrolyt te inGram ram equ uivalvalentsts/l lit ter r. C C =

17、1 1/R = caca/11000 l lRes sistastanc ce is s inv versrsel ly proport proportio onal to thal to the co conc centrattratio on.REFRACCTI IVE IND INDEX D DETECCTOORREFRACCTI IVE IND INDEX D DETECCTOOR Th he r refractfractiv ve index det tector ctor is ths the last cho last choic ce det tectorctor.It It

18、is ths the l least sast sens sit tiv ve s sens sit tiv ve det tectorctor. It It is ss sens sit tiv veTo chao changes s in amb ambient tt tempmperaturrature a and pr pressurssure a andFlow ratlow rate. It ca It can o onl ly b be us used w with th isocratsocratic c elutlutio ons s And is us unsusuitab

19、ltable for for graradient t elutlutio ons s.It coIt cons sists of thsts of the follow following compo componentsts:11. . A l light sourcht source wh which ch is usualls usually tu tungststen lamp lamp.22. An opt optical mascal mask co conf fines ths the b beam to tham to the r regio on of th of theC

20、Cellll.33. A l lens colls collimatmates ths the l light bht beam wham which thch then pass passes s throuthrough both thh both the sampl sample a and r ref fer renc ce c cells to a plalls to a planeM Mirrorrror.44. Th he m mirror rrror reflflects thcts the b beam bacam back throu through thh the sam

21、pl sampleREFRACCTI IVE IND INDEX D DETECCTOOR (CON(CONTD)D)5. Th he locat locatio on of th of the b beam ratham rather thar than its ts int tens sit ty is sD Det termrmined b by th the a angular ular deflflectctio on of th of the b beam causam causedBy th the r refractfractiv ve index diffffer renc

22、ce b betwtween th the co cont tentstsOf thOf the two c two cellslls.66. As ths the b beam chaam changes ths the pos posit tio on of focus o of focus on th the Photohotoel lectrctric cc cellll, th the output cha output changes as and th the r resultsulting D Diffffer renc ce s signal al is s el lectr

23、octronicallcally mo modif fied to prov to provide a a Signal proportal proportio onal to thal to the co conc centrattratio on of solut of solute in th theSamplample c cellll.REFRACCTI IVE IND INDEX D DETECCTOOR (CON(CONTD)D)ION CION CHROMOMATOOGRAPHYIoIon Chromato Chromatographraphy is bass based o

24、on th the exchachange of of io ons ofs ofLLike char charge b betwtween th the solut solutio on a and th the stat statio onarary phas phase.ION CION CHROMOMATOOGRAPHY (CON (CONTD)D)Th he equ uil librbria a involvvolved in cat catio on aand a anio on exchachange chromatochromatographraphy ar are:ION C

25、ION CHROMOMATOOGRAPHY (CON (CONTD)D)Wh hen ION CION CHROMOMATOOGRAPHY (CON (CONTD)D)K K decrcreasases s in th the or order for Mr for M+ io ons sTl l+ Ag+CsCs+ Rb b+KK+NNH44+NaNa+LLi+Th he or order for ar for anio ons s is s Th hes se or orders arrs are bas based o on th the io onic rac radii of th

26、of the var variousous io ons s.ION CION CHROMOMATOOGRAPHY (CON (CONTD)D)OSO-OONa+Sodium Dodecyl SulfateCH3CH3CH3NCH3+Br- Octyltrimethylammonium BromideION CION CHROMOMATOOGRAPHY (CON (CONTD)D)H3CSO4-CH3SiCH3CH3H3CSO4-CH3SiCH3CH3+2+MM2+K0SiCH3CH3CH3H3CSO4+ HL+ ML+H+SiCH3CH3CH3H3CSO4-M+K1SI IZE EXCLUC

27、LUSION CION CHROMOMATOOGRAPHYIt It is also s also knowown as as gel pl permrmeatatio on or or gel fl filtratltratio onChromatoChromatographraphy. As ths the namame implmplies ths the s separatparatio onIs basIs based o on th the s size of th of the a analalyt te mol moleculcules s. Th heStattatio on

28、arary phas phase co contatains fas fairlrly lar large 1 10 m um uniformformSi or polor polym mer partr particlcles s. Analalyt te a and solv solvent molt moleculcules s D Diffusffuse in a and out of th out of the por pores of ths of thes se part particlcles s.Ret tent tio on of th of the a analalyt

29、te dep pends os on th the por pore s size a and th theSize of th of the mol moleculcule. It It is thus s thus importamportant that tht that the por poreSize b be in th the ra range of of diamamet ters of thrs of the mol moleculcules sBeing s separatparated. If th If the mol molecular cular diamamet

30、ter r is ss signif ficacantltlySmallmaller thar than th the por pore diamamet ter thr they w will sll simplmply b be Washashed out u out unr retatained.SI IZE EXCLUCLUSION CION CHROMOMATOOGRAPHY (CON(CONTD)D)Size exclusclusio on is ofts often appl applied to lar to large mol moleculcules suchs suchA

31、s pols polym mersrs, prot proteins s etctc.SI IZE EXCLUCLUSION CION CHROMOMATOOGRAPHY (CON(CONTD)D)Th he total volum total volume of a pac of a packed s size exclusclusio on colum column is s Vt t = Vg + Vi + Vo o Vt t = total volum total volume; Vg = volum volume occup occupied b by th the sol soli

32、d matr matrix of th of the gel (statl (statio onarary phas phase) ) Vi = volum volume of th of the solv solvent ht hel ld in th the por pores s Vo o = fr free volum volume outs outside th the gel partl particlcles sTh he r ret tent tio on volum volume for mol for moleculcules too lars too large to to ent ter thr thePorores s = Vo o Ret tent tio on volum volume for mol for moleculcules too small to bs too small to be r retatainedI In th the por pores s = Vi + Vo o SI IZE EXCLUCLUSION CION CHROMOMATOOGRAPHY (CON(CONTD)D)MolMoleculcules of s of int